Re: [PATCH] crypto - shash: reduce minimum alignment of shash_desc structure
flat view
From: Ard Biesheuvel <ardb@kernel.org>
Date: 2021-01-08 11:32:54
Also in:
linux-crypto
On Fri, 8 Jan 2021 at 11:59, Arnd Bergmann [off-list ref] wrote:
On Fri, Jan 8, 2021 at 11:44 AM Herbert Xu [off-list ref] wrote:quoted
On Fri, Jan 08, 2021 at 11:42:53AM +0100, Arnd Bergmann wrote:quoted
How does this work for kernels with CONFIG_VMAP_STACK? I remember some other subsystems (usb, hid) adding workarounds for that, but I don't see those in drivers/cryptoI'm referring to the situation in general and not the subject of this thread. For shash_desc of course it doesn't happen since it sync only.Ah, got it.
I can fold in the following
--- a/include/linux/crypto.h
+++ b/include/linux/crypto.h@@ -151,9 +151,12 @@ * The macro CRYPTO_MINALIGN_ATTR (along with the void * type in the actual * declaration) is used to ensure that the crypto_tfm context structure is * aligned correctly for the given architecture so that there are no alignment - * faults for C data types. In particular, this is required on platforms such - * as arm where pointers are 32-bit aligned but there are data types such as - * u64 which require 64-bit alignment. + * faults for C data types. On architectures that support non-cache coherent + * DMA, such as ARM or arm64, it also takes into account the minimal alignment + * that is required to ensure that the context struct member does not share any + * cachelines with the rest of the struct. This is needed to ensure that cache + * maintenance for non-coherent DMA does not affect data that may be accessed + * by the CPU concurrently. */ #define CRYPTO_MINALIGN ARCH_KMALLOC_MINALIGN
(or send it as a separate patch) Note that the comment about 64-bit alignment for 64-bit types on ARM is incorrect. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel